In a network environment, routers are typically used to transfer data packets from one network, such as a Local Area Network (LAN) or a Wide Area Network (WAN) to another. Routers are also used to balance traffic within workgroups of a network. Routers can also provide filtering of inter or intra network traffic for security purposes and policy management.
A number of routers can be connected between a number of network clients and various network equipment. In some situations, these routers can go offline or malfunction. For example, during a power outage the router may lose power and the network connection is lost. Additionally, a router can become overloaded with information and can shut itself down to protect itself or can be overwhelmed by the information such that the router becomes “frozen.” In such cases, the data in transit through the router can be lost.
Thus, router redundancy protocols (RRPs), such as the Virtual Router Redundancy Protocol (VRRP) have been developed to allow a number of routers to be configured in a redundant manner. A pair (or more) of VRRP routers ensures connectivity of hosts in a LAN by providing a backup of the default gateway functionality. The Master VRRP router acts as the default gateway and forwards packets sent by the hosts in the VRRP Virtual LAN (Vlan). On the failure of the Master VRRP router due to local or network events, the highest priority Backup VRRP router takes control and provides the default gateway functionality for the hosts in the Vlan. By doing so, it prevents the loss of network connectivity to hosts in the LAN.